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Institute
- Zentrum für Forschung, Entwicklung und Transfer (80) (remove)
The indigenous hardwoods in German forests have a substantial ability to store carbon, and forestry reconstruction measures are anticipated to result in an increase in availability of hardwood on the wood market. Despite this, its material usage is declining with over two thirds of the harvested quantity being used for energy production. This study aims to identify policy measures and promising strategies for increasing hardwood utilisation using a combined policy Delphi-SWOT approach with literature review undertaken to identify the barriers and driving factors for an increase in its material use. The results were then ranked by a panel of experts and used as basis for the SWOT analysis, which was then applied to an extended SWOT approach. The resulting strategies were then discussed by the panel and ranked further in the 2nd and 3rd Delphi round. After three Delphi rounds, three strategies and associated policy recommendations were ranked as most effective by the experts: innovative hardwood products including manufacturing processes, research transfer and lobbying. This study provides both strategic analyses and effective strategies to stimulate the production of hardwood-based products and ends with a concise description of these strategies and policy recommendations, which are benchmarked against current literature and best practise examples.
Die Charakterisierung und Quantifizierung von Phytoplankton-Gemeinschaften sind ein wesentlicher Aspekt der Gütebeurteilung von Standgewässern. In dieser Arbeit wird eine neue Herangehensweise hergeleitet und demonstriert, welche die klassische, taxonomisch-orientierte Methodik durch einen funktionalen Ansatz ergänzt, der auf den physiologischen und ökologischen Eigenschaften der Taxa (Traits) beruht. Kern des Ansatzes bildet der sogenannte Trait-Schlüssel, mit dem eine taxonomische Information in eine funktionale Information übersetzt werden kann. Die Aussagekraft und Potenziale des Verfahrens werden anhand von Langzeitdaten (50 Jahre) der Phytoplankton-Gemeinschaft der Rappbode-Talsperre exemplarisch demonstriert. Die Trait-basierte Analyse reduziert die Komplexität der Daten und ermöglicht eine quantitative Analyse der beobachteten Veränderungen auf der Basis von statistischen Methoden, die auf den klassischen taxonomischen Ansatz nicht anwendbar sind. Sowohl hinsichtlich der saisonalen Sukzession als auch der langfristigen Trends lassen die funktionalen Eigenschaften Rückschlüsse auf die maßgeblichen Umweltfaktoren zu. Für die wasserwirtschaftliche Praxis erweitert sich damit der Informationsgehalt und die Interpretierbarkeit der vorhandenen Daten. Diese Aufwertung der Ergebnisse kann ohne Mehraufwand erhalten werden. Von besonderem Interesse sind hierbei Kausalanalysen signifikanter Langzeittrends oder von sprunghaften Veränderungen in der Phytoplankton-Entwicklung, die hiermit in einen kausalen und systemanalytischen Zusammenhang gestellt werden können.
Background
Vertigo, dizziness and balance disorders (VDB) are among the most relevant contributors to the burden of disability among older adults living in the community and associated with immobility, limitations of activities of daily living and decreased participation. The aim of this study was to identify the quality of evidence of physical therapy interventions that address mobility and participation in older patients with VDB and to characterize the used primary and secondary outcomes.
Methods
A systematic search via MEDLINE (PubMed), Cochrane Library, CINAHL, PEDro, forward citation tracing and hand search was conducted initially in 11/2017 and updated in 7/2019. We included individual and cluster-randomized controlled trials and trials with quasi-experimental design, published between 2007 and 2017/2019 and including individuals ≥65 years with VDB. Physical therapy and related interventions were reviewed with no restrictions to outcome measurement. Screening of titles, abstracts and full texts, data extraction and critical appraisal was conducted by two independent researchers. The included studies were heterogeneous in terms of interventions and outcome measures. Therefore, a narrative synthesis was conducted.
Results
A total of 20 randomized and 2 non-randomized controlled trials with 1876 patients met the inclusion criteria. The included studies were heterogeneous in terms of complexity of interventions, outcome measures and methodological quality. Vestibular rehabilitation (VR) was examined in twelve studies, computer-assisted VR (CAVR) in five, Tai Chi as VR (TCVR) in three, canal repositioning manoeuvres (CRM) in one and manual therapy (MT) in one study. Mixed effects were found regarding body structure/function and activities/participation. Quality of life and/or falls were assessed, with no differences between groups. VR is with moderate quality of evidence superior to usual care to improve balance, mobility and symptoms.
Conclusion
To treat older individuals with VDB, VR in any variation and in addition to CRMs seems to be effective. High-quality randomized trials need to be conducted to inform clinical decision making.
Trial registration
PROSPERO 2017 CRD42017080291.
A crucial problem in concrete engineering is the corrosion of steel reinforcements. Polymer fibers as alternative reinforcement material can prevent corrosion; however, high adhesion to concrete and good fiber mechanics are necessary for polymers to be considered as an alternative reinforcement. This study tested different thermoplastic polymer materials to evaluate their level of adhesion to concrete. The adhesion properties of different self‐drawn polymer fibers were analyzed by extracting the fibers from concrete using single fiber pull‐out test (SFPT). To determine the adhesion mechanism, different polymer properties were analyzed and correlated to SFPT. Strong evidence was found that the fibers mechanical properties correlate with SFPT. Roughening the fiber surface increases the SFPT results significantly. While highly polar materials can support the adhesion process, a clear correlation could not be found. This study identifies high stiffness and roughness as the crucial properties of polymer fibers used in concrete engineering. If these factors can be engineered into the fiber, polymer fibers can present an alternative to steel in concrete reinforcement.
This paper presents a systematic literature review on both the risks affecting wood supply security and risk mitigation strategies by quantitative and qualitative data analysis. It describes wood-specific supply chain risks, thereupon resulting impacts and counteracting strategies to ensure supply. Risks, impacts, and strategies are documented as basis for a comparative analysis, discussion of results, challenges and research gaps. Finally, the suitability and the limitations of the chosen methodology and the achieved results are discussed. Scanning wood supply chain risks and supply strategies, most of the reviewed papers focus on wood supply for bioenergy generation and only a few studies investigate wood supply chain risk issues for the sawing, wood panel, pulp and paper industries, or biorefineries.
This review differs significantly from other reviews in this field as it considers the entire wood value chain including recent studies on new chemical wood-based products and thus provides a more complete picture of the wood-based bioeconomy. Consequently, it contributes to the literature by providing an overarching investigation of the risks affecting wood supply security and possible side effects of a growing wood-based bioeconomy. It was found that comprehensive value chain analyses considering established wood products, large-volume bioenergy products, as well as established and new chemical wood-based products in the context of wood supply security are missing. Studies that map the entire wood value chain with its multilevel interdependences and integrating cascading use of wood are lacking.
In the project, domestic ventilation concepts with PushPull-Fans were investigated. These ventilation units are characterized by a periodically changing supply and exhaust air operation. To ensure balanced operation, these ventilation units are always used in pairs, with one unit being in the exhaust air mode and the other in supply air mode. Measurements were made in a research apartment. The results were used to validate a CFD simulation model for transient studies. A room-by-room layout with two units in one room and a cross-room ventilation layout with two connected units in two rooms were analysed. The age of air was used as the evaluation parameter. With the room-by-room ventilation layout a lower age of air in the bedroom compared to the cross-room layout was obtained. However, in the room-by-room layout, the air flow through the larger living room with connected corridor was poorer in the rear area. With the cross-room layout, the flow through the rooms was more uniform. With the cross-room layout, the average age of air in the apartment could be slightly reduced compared to the room-by-room layout.
In dieser Arbeit wurden unterschiedliche Regler für Wohnraumlüftungsanlagen untersucht. Als Bewertungsgrößen wurden die Lüftungswärmeverluste und die kumulierte Grenzwertüberschreitung für CO2 und relative Luftfeuchte verwendet. Dafür wurde in Matlab/Simulink ein Multizonen-Simulationsmodell erstellt. Untersucht wurde ein zentrales, ein dezentrales alternierendes (Pendellüftung) sowie ein nichtalternierendes (Einzelraumlüftung) Lüftungssystem. Jedes der Lüftungssysteme wurde mit konstantem Volumenstrom, einem PI- und einem Fuzzy-Regler (Ausnahme: Pendellüftung) simuliert. Gegenüber einem Lüftungssystem mit konstantem Volumenstrom, kann durch Regelung bei mindestens gleicher Luftqualität der Lüftungswärmeverlust um mindestens ein Drittel reduziert werden.
Meeting ecological and water quality standards in lotic ecosystems is often failed due to multiple stressors. However, disentangling stressor effects and identifying relevant stressor-effect-relationships in complex environmental settings remain major challenges. By combining state-of-the-art methods from ecotoxicology and aquatic ecosystem analysis, we aimed here to disentangle the effects of multiple chemical and non-chemical stressors along a longitudinal land use gradient in a third-order river in Germany. We distinguished and evaluated four dominant stressor categories along this gradient: (1) Hydromorphological alterations: Flow diversity and substrate diversity correlated with the EU-Water Framework Directive based indicators for the quality element macroinvertebrates, which deteriorated at the transition from near-natural reference sites to urban sites. (2) Elevated nutrient levels and eutrophication: Low to moderate nutrient concentrations together with complete canopy cover at the reference sites correlated with low densities of benthic algae (biofilms). We found no more systematic relation of algal density with nutrient concentrations at the downstream sites, suggesting that limiting concentrations are exceeded already at moderate nutrient concentrations and reduced shading by riparian vegetation. (3) Elevated organic matter levels: Wastewater treatment plants (WWTP) and stormwater drainage systems were the primary sources of bioavailable dissolved organic carbon. Consequently, planktonic bacterial production and especially extracellular enzyme activity increased downstream of those effluents showing local peaks. (4) Micropollutants and toxicity-related stress: WWTPs were the predominant source of toxic stress, resulting in a rapid increase of the toxicity for invertebrates and algae with only one order of magnitude below the acute toxic levels. This toxicity correlates negatively with the contribution of invertebrate species being sensitive towards pesticides (SPEARpesticides index), probably contributing to the loss of biodiversity recorded in response to WWTP effluents. Our longitudinal approach highlights the potential of coordinated community efforts in supplementing established monitoring methods to tackle the complex phenomenon of multiple stress.
Many doubts accompany both the resource potential of hardwoods and their softwood substituting potential within its material utilisation. However, as the feedstock demand will rise with more and more wood-based biorefineries entering the market, wood supply security is an increasingly pressing topic. Currently, hardwood flow models are lacking, but are an essential basis for estimating future hardwood supply security. This study investigates the actual hardwood flows in Germany by applying a Material Flow Analysis (MFA). Visualising the results of the MFA for the reference year 2016. The MFA displays 4.44 +/- 0.12 million m³ (fob) recorded fellings in privately-owned forests, 8.60 +/- 0.15 million m³ (fob) recorded fellings in state forests, 9.31 +/- 0.52 million m³ (fob) as unrecorded harvest from forests (i.e. 37% of the total harvest) and 2.65 +/- 0.35 million m³ (fob) unrecorded fellings from non-forest area (11% of total harvest). Of that, almost 30% were used for materials and 70% were used for energy. Consequently, the potential for material use of hardwood in Germany lies beyond its current usage, especially given that good qualities are being used for energy due to actual low material consumer demand. Thus, the MFA assessed the quality and quantity of the German hardwood potential and showed that it offers significant possibilities for value added usage options such as, for example, producing innovative products in biorefineries using degraded high-quality assortments. Due to the low data consistency, heterogeneous datasets for the forest and wood industry sector were calibrated through data reconciliation and error propagation. Additionally, the lack of statistical data for specific wood industry sectors raised a problem, for instance, actual data on private combustion of wood, established hardwood uses, or new innovative products. Severe data issues regarding the German hardwood flow were confirmed.
Modern production facilities are becoming increasingly complex, as companies battle to meet the increasingly customer-specific demands with shorter lead times and higher efficiency. For the employees in the factory, who often bear the brunt of making short-term process decisions, this complexity is becoming unmanageable. The PhD project presented in the following aims to decrease the complexity of modern manufactory facilities by means of artificial intelligence. The focus is on product data analysis and manufactory process planning. Different approaches of artificial intelligence for use in a Self-Adapting Smart System (SASS) are to be investigated.
Driving forest machines on wet soils causes irreversible soil compaction, often associated with intensive rut formation and inaccessibility of wheeled forest machines for future forest operations. The German forestry equipment manufacturer FHS, Forsttechnik Handel & Service GmbH, engineered a forwarder, the Trac 81/11, equipped with conventional, well-proved bogie-axles embraced by a closed rubber track. At the center of the bogie-axle, four additional supportive rollers are placed to increase the load-carrying section between the tires of the bogie-axle. The study aimed to characterize the principle concept and the trafficability of the forwarder by analyzing the footprint area, the contact pressure, the rut formation on forest sites and the slippage during driving. Therefore, the effective contact area was measured on steel plates and rut formation was analyzed on a case study basis. Results showed that the supportive rollers increase the contact surface area by about 1/3. By this, a decrease of peak loads below the wheels and a more homogenous load distribution were observed. However, the contact surface area is still clearly divided into three parts; the area between the supportive rollers and the wheels does not take any load. Results of the rut formation were diverse: After 20 passes with 26,700 kg total mass, rut depth varied between 12.6 and 212.5 mm. Overall, the new undercarriage concept of FHS demonstrated a generally positive performance. The engineered forwarder contributes to reduce the environmental impact associated with log extraction.
Aquifers are typically perceived as rather stable habitats, characterized by low biogeochemical and microbial community dynamics. Upon contamination, aquifers shift to a perturbed ecological status, in which specialized populations of contaminant degraders establish and mediate aquifer restoration. However, the ecological controls of such degrader populations, and possible feedbacks between hydraulic and microbial habitat components, remain poorly understood. Here, we provide evidence of such couplings, via 4 years of annual sampling of groundwater and sediments across a high-resolution depth-transect of a hydrocarbon plume. Specialized anaerobic degrader populations are known to be established at the reactive fringes of the plume. Here, we show that fluctuations of the groundwater table were paralleled by pronounced dynamics of biogeochemical processes, pollutant degradation, and plume microbiota. Importantly, a switching in maximal relative abundance between dominant degrader populations within the Desulfobulbaceae and Desulfosporosinus spp. was observed after hydraulic dynamics. Thus, functional redundancy amongst anaerobic hydrocarbon degraders could have been relevant in sustaining biodegradation processes after hydraulic fluctuations. These findings contribute to an improved ecological perspective of contaminant plumes as a dynamic microbial habitat, with implications for both monitoring and remediation strategies in situ.
The use of wood in geotechnical applications has seen renewed interest. However, concerns related to the durability and service life of wood in ground contact applications remain. Wood has the potential to substitute commonly used steel and concrete in the geotechnical engineering sector, but solutions to extending the service life and maintenance intervals require long-lasting wood protection systems capable of inhibiting fungal and bacterial decay. Cement, one of the constituents of concrete was identified as a potential coating material for wood used in soil stabilisation works. Spruce and beech wood rest rolls from commercial veneer peeling has been identified as a potential source for cement-coated geotechnical wood products. Norway spruce and European beech wood was subsequently used in this study.
In this study, a series of tests related to dimensional stability and fungal durability were undertaken to investigate the adhesion of a cement coating to wood and to assess the effect of a cement coating on the resistance to fungal decay. Swelling and shrinkage tests of uncoated specimens were undertaken to investigate dimensional stability. Laboratory fungal durability tests assessed changes in wood durability of specimens coated with a novel, flexural cement coating. Wood impregnated with Polyethyleneglycol-dimethacrylate (PEGDMA) prior to cement coating was investigated to improve wood dimensional stability and reduce cracking of the cement coating under changing wood moisture conditions. Cement coating thickness and delamination tests then assessed the durability of the novel cement coating itself. Results from fungal durability tests showed that a continuous, flexural, and crack-free cement coating was imperative to a wood durability improvement. Double cement-coated spruce wood showed improved resistance to decay by basidiomycetes (Coniphora puteana and Trametes versicolor). Results from swelling and shrinkage tests showed that an improvement in dimensional stability would assist in achieving a durable cement coating and impregnation with Polyethyleneglycol-dimethacrylate (PEGDMA) is one manner to improve dimensional stability and therefore cement adhesion to the wood substrate.
When monitoring the energy performance of buildings, it may be of interest to identify the occupation periods of people in the room due to their possible impact on the energy balance. In order to be able to carry out a comprehensive energy assessment of the system and building, it is necessary to be able to classify user influence during the evaluation. This thesis investigates how the presence of people in a room can be determined cost-effectively and with little additional effort. The aim is to determine which sensors of a room control system provide sufficiently reliable data. The presence of 1-2 persons was examined on a test facility of the Technical University Rosenheim. The air-, mean radiation- and surface-temperatures, the air humidity as well as the CO2 and VOC concentrations were measured. For the analysis, a method of supervised machine and statistical learning, random forest, is used. The smallest model error detected in predicting the presence of 1 or 2 persons from CO2 sensor data is 1.43%. The error rates are low for all tested models if time-dynamic effects are used as predictors and the data is processed in a so-called time period form. Additionally, the ways in which this data should ideally be made available for future measurements and processed to facilitate analysis with machine and statistical learning techniques have been investigated. A further goal is to apply the models developed on measurement series in laboratory environments to real rooms and to assess the transferability of these models.
1. Understanding and explaining the structure of communities in response to environmental gradients is a central goal in ecology. Trait‐based approaches are promising but yet rarely applied to understand community dynamics in response to changing environmental conditions.
2. Here, we investigate seasonal succession patterns of functional traits in phytoplankton communities and how nutrient reductions (oligotrophication) alter these patterns. We used phytoplankton data from 40 years of observation from the Rappbode Reservoir (Germany), which underwent a strong shift in trophic conditions, and translated taxonomic composition into functional traits by assigning trait values compiled from the literature.
3. All studied traits (morphological, behavioural and physiological traits) responded to changing environmental conditions and showed consistent, reoccurring seasonal developments. The seasonal succession of phytoplankton communities was shaped by a trade‐off between small‐celled, fast‐growing species that are able to rapidly incorporate existing resources (r ‐strategists) and large‐celled species with more complex and efficient mechanisms to exploit scarce mineral nutrients or acquire previously unexploited nutrient pools (k ‐strategists). In summer, when nutrients were scarce, the k ‐strategy was prevailing (important traits: phosphate affinity, nitrogen fixation, motility and mixotrophy). During the rest of the year, nutrients and turbulence were high and r ‐strategists dominated (important traits: maximum growth rate and light affinity).
4. A comparison between eutrophic and oligotrophic years revealed that the main features of functional trait succession were largely preserved, but intra‐annual fluctuations from spring to summer were stronger during eutrophic years. Nutrient reductions mainly affected functional traits and biomass in spring, while in summer the functional community composition changed little.
5. Synthesis. This study provides for the first time a quantitatively supported functional template for trait‐based succession patterns in lakes under different nutrient conditions. By translating taxonomic composition into trait information, we demonstrate that the quantification of functional characteristics enables ecological interpretation of observed community dynamics and provides not only a testable template but also a powerful tool towards a more mechanistic understanding. The quantification of functional traits further improves the predictability of community shifts in response to changing environmental conditions and thus opens new perspectives for predictive limnology using lake ecosystem models.
We employed the well-established Horton-Strahler, hierarchical, stream-order (ω) scheme to investigate scaling of nutrient loads (P and N) from ~845 wastewater treatment plants (WWTPs) distributed along the river network in urbanized Weser River, the largest national basin in Germany (~46K km2; ~8.4 million population). We estimated hydrologic and water quality impacts at the reach- and basin-scales, at two steady river discharge conditions (median flow, QR50; low-flow, QR90). Of the five WWTPs class-sizes (1 ≤ k ≤ 5), ~68% discharge to small low-order streams (ω < 3). We found large variations in capacity to dilute WWTP nutrient loads because of variability in (1) treated wastewater discharge (QU) within and among different class-sizes, and (2) river discharge (QR) within low-order streams (ω < 3) resulting from differences in drainage areas. For QR50, reach-scale water quality impairment assessed by nutrient concentration was likely at 136 (~16%) locations for P and 15 locations (~2%) for N. About 90% of these locations were lower-order streams (ω < 3). At QR50 and only with dilution, basin-scale cumulative nutrient loads from multiple upstream WWTPs increase impaired locations to 266 (~32% of total) for P. Considering in-stream uptake decreased P-impaired streams to 225 (~27%), suggesting the dominant role of dilution in the Weser River basin. Role of in-stream uptake diminished along the flow paths, while dilution in larger streams (4 ≤ ω ≤ 7) minimizes the impact of WWTP loads. Under QR90 conditions [(QR50/QR90) ~ 2.5], water quality impaired locations will likely double for the basin-scale analyses. Long-term water quality data suggested that diffuse sources are the primary contributors for water quality impairments in large streams. Our data-modeling synthesis approach is transferable to other urbanized river basins and extends understanding of point source impacts on water quality across spatial scales.